package Exercise;

import java.util.Scanner;

public class demo11 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int m = sc.nextInt();
        int n = sc.nextInt();
        int [][] arr = new int[100][100];

        for (int i = 0; i < arr.length; i++) {
            for (int j = 0; j <= i; j++) {
                if(j == 0 || i==j){
                    arr[i][j] = 1;
                }
                else{
                    arr[i][j] = arr[i-1][j-1] + arr[i-1][j];
                }
            }
        }
        System.out.println(arr[m-1][n-1]);
    }
}
